Whole story with images:
http://www.psi.edu/pgwg/images/aug09image.html
"Several of the streaks are triggered by impact craters
that have dark ejecta."
"Other interesting observations include triggering of
slope streaks by an impact crater, blast from an impact
explosion, or boulders rolling or bouncing downslope,
and formation of long linear ridges within the streak
that are parallel to its margins."
Source: Paul H., Baton Rouge, LA, USA
